Submergible barge structure for off-shore operations



J. DAVIDON March 19, 1963 SUBMERGIBLE BARGE STRUCTURE FOR OFFSHOREOPERATIONS Filed NOV. 8, 1955 4 Sheets-Sheet l INVENTOR JHCK D4 wan/v$34 in Z52 March 19, 1963 J. DAVIDON 3,081,600

SUBMERGIBLE BARGE STRUCTURE FOR OFF-SHORE OPERATIONS Filed Nov. 8, 19554 Sheets-Sheet 2 INVENTOR.

HTTOI /VEVS III|AIIII||IIIII|IIIIIIJw I ll March 19, 1963 J. DAVIDON3,081,600

SUBMERGIBLE BARGE STRUCTURE FOR OFF-SHORE OPERATIONS Filed Nov. 8, 19554 Sheets-Sheet 3 TILT E l7 D/SCH/IEGE OUTLET FLOOD VAL 1 55 a AND , gO/MM CHA 55/2 L CH 52 UPPEK BAWGE 451 51 M 74KE SEACMK G Cf/AM BER Q lib' CHAM BER 1i UHHM BEE l:

? PUMPS i a fOa CHAMEEE Q CAM/W558 GHAM BBQ .5

115/ INT/1K5 554cm? 1014 5? BAKGE Lil 1 INVENTOR. Jilck D4 r/w/v mf waxMarch 19, 1963 J. DAVIDON 3,081,600

SUBMERGIBLE BARGE STRUCTURE FOR OFF-SHORE OPERATIONS Filed Nov. 8, 19554 Sheets-Sheet 4 Tic. E.

IN VEN TOR. JJCK DA woo/v YWW United States Patent 9 i 3,081,600SUBMERGIBLE BARGE STRUCTURE FOR OFF-SHORE OPERATIONS Jack Davidon,Forest Hills, N.Y., assignor to Merritt- Chapman & Scott Corporation,New York, N.Y., a

corporation of New York Filed Nov. 8, 1955, Ser. No. 545,733 4 Claims.01. 61-465) The present invention relates to submergible floatingstructures for off-shore operations, and more particularly to apparatusand techniques for raising and lowering such structures.

For the purpose of drilling oil wells in open sea areas, it is known tomake use of floating barges which may be towed to a desired site andthen submerged completely beneath the surface of the water. Supported onthe barge is a superstructure adapted to project above the water surfacewhen the barge lies on the ocean floor, the superstructure including aworking platform or deck. Oceanographic and meterological conditionsmust of course be taken into account in the design of such submergiblestructures. It has been found, for example, that heavy winds andbreaking waves may cause objectionable sliding of the submerged bargedespite the great bulk of the barge and the load imposed thereon by thesuperstructure.

Accordingly, it is the principal object of this invention to provide afloating structure which can be sunk in deep open waters subject totides and heavy wave action as well as to hurricane winds, and whichwhen submerged will afford a firm, stable base on beds of varyingbearing capacity.

More particularly, it is an object of this invention to provide asubmergible barge so constructed and shaped that when the barge is sunkand set on its bed, it will offer great resistance to lateral forces dueto wave action and wind pressure.

A further object of the invention is to provide a barge incorporatingwithin its body apparatus for submerging and raising itself, said bargewhen submerged affording a stable foundation for a working platform .inwaters of various depths. From this platform one may conductwell-drilling, pile driving and pumping operations or the constructionof permanent marine stations.

Yet another object of the invention is to provide a barge structurewhich is provided with spud means to maintain stability during thesinking or raising thereof and which acts firmly to anchor the barge onthe ocean bed.

A barge structure in accordance with the invention is provided withhollow shafts on the top of which is securely mounted a working platformor superstructure. The unit is designed to float with its normalsuperstructure above water level and when submerged to have itssuperstructure constitute a safe support for any load imposed thereon,such as drilling rigs and other machinery. The barge is constituted bytwo superposed levels, each divided into water-tight chambers orcompartments. Installed in selected dry compartments are pumps, pipesand valve means adapted to permit water to enter into or be dischargedfrom the wet compartments and to control the sinking or refloating ofthe barge.

The construction of the barge is such that for reasons of stability whenoperating in 'waters exposed to heavy wave action, the base will beadequately bulky and of sufiicient weight such that the working platformof the superstructure can be placed at a proper distance above the meanlow water level as to be above the crest of the waves of full gale orhurricane force. Such superstructure is so designed that it offersminimum resistance to such wave action. An important feature of theinvention resides in the wafile or grid-like construction of the exposedbottom or base of the barge which acts as a gripping tread or 3,081,600Patented Mar. 19, 1963 anchor on the ocean floor to prevent lateraldisplacement of the submerged barge.

The barge may be equipped with pontoons which can be used during thesinking or raising of the barge to aid in the control of its buoyancyand stability. These pontoons may be mounted on the barge at whateverlocation is deemed most desirable for the use to which the floatingstructure is to be put. The barge is also equipped with spud piles whichcan be employed during the raising 0r lowering of the barge to aid incontrolling its stability, and the number and location of the spuds maybe such as deemed most desirable for the use to which the structure isto be put. The spuds further serve to pin the barge to the bottom and toprevent lateral movement of the submerged barge.

For a better understanding of the invention as well as other objects andfurther features thereof, reference is had to the following detaileddescription to be read in conjunction with the accompanying drawing,wherein like components in the various views are identified by likereference numerals.

In the drawing:

FIGURE 1 is a vertical section taken through a preferred embodiment of asubmergible barge structure in accordance with the invention.

FIGURE 2 is a horizontal section taken along the several planesextending through lines 22 in FIG. 1.

FIGURE 3 is an enlarged sectional view of one of the spuds illustratedin FIGURE 1.

FIGURE 4 is a horizontal section taken along the plane extending throughline 4-4 in FIG. 1.

FIGURE 5 is a horizontal section taken. along the plane extendingthrough lines 5-5 in FIG. 1.

FIGURE 6 is a vertical section through one of the spuds showing thebarge afloat and the spuds in an elevated position.

FIGURE 7 shows the raising or lowering of the barge with the spuds setin the ocean bottom.

FIGURE 8 is a transverse section taken through one of the shafts.

Referring now to the drawings and more particularly to FIG. 1, thestructure in accordance with the invention comprises a buoyant hollowbarge, generally designated by numeral 10, a plurality of hollow shafts,generally designated by numeral 11, extending vertically from the barge,and a deck or working platform 12 supported at the upper ends of theshafts. The barge and the shafts preferably are fabricated of reinforcedconcrete.

Barge 10 is of rectangular shape and is constituted by superposed upperand lower levels 10a and 10b, respectively, each level being divided bylongitudinal and transverse partitions or bulk-heads into a plurality ofwatertight compartments. Selected wet compartments are adapted to befilled or partially filled with water for varying the buoyancy of thebarge, the remaining dry compartments being used for pumps and the like.

As shown separately in plan view in FIG. 4, the lower level 10a ispartitioned into water-tight compartments defining nine chambers A to I,the chambers G, H and I being in the middle of the barge. Installed inthe dry chamber H are suitable pump or air jet means for expelling Waterfrom the compartments, valve means being provided for individuallycontrolling the flooding or emptying of the various compartments. Theupper level 10b, as shown in FIG, 5, is divided into chambers I to P,the middle chamber P being a dry chamber reserved for flood valves aswell as for storage purposes. It will be seen therefore that the wetchambers on both levels are symmetrically disposed on either side of thedry chambers.

At least the chambers G and I in the lower level or chamber P in theupper level are provided with intake sea-cocks at positions 13 and i4,and the remaining wet compartments are provided with pipes and valves bythe operation of which all the wet compartments may be put intocommunication with the sea-cocks to permit a predetermined volume ofwater to enter into any or all of the wet compartments, thereby tocontrol the sinking of the barge at a predetermined rate and to governthe pressure imposed at the bottom of the ocean when the barge is fullysubmerged and set in place.

The pumps in chamber H in the lower level are coupled to dischargeoutlets and 16 at either end of the chamber P in the upper level. Agiven volume of water may be removed by means of the pumps, theassociated pipes and valves from any or all the compartments to controlstability of the barge as well as its refloating at a predeterminedrate. Devices of standard construction are provided to govern the rateof inflow of the Water into each wet compartment so as to keep the bargein a level position during its sinking, and similarly to regulate theexpulsion of water when refloating.

As best seen in FIGS. 2 and 3, the bottom or base 17 of the barge isconstructed in the form of a waffle or grid having projecting ridges 18,such that when the barge is resting on the bottom of the seas, itsweight and the load superimposed thereon by the platform will impressthe bottom-of the barge into the soil 19. The ridges 18 act as teethwhich cut into the soil, thus offering great resistance to any tendencyof the barge to slide as a result of breaking waves or heavy winds.

The vertical shafts 11 are cylindrical in shape and are of suflicientheight and strength to transmit to the barge 10 all the vertical andhorizontal loads to which it may be subjected. In the embodiment shown,six shafts are provided, four of the shafts being positioned adjacentthe four corners of the barge, the remaining two being positioned at themiddle of the barge adjacent the sides. In order to raise or lowerpersonnel and equipment into the storage and pumping chambers, one orboth of the center shafts may have an elevator installed therein, theelevator operating between the working deck 12 and the chamber P in theupper level of the barge.

The deck 12, as best seen in FIG. 2, is provided at one end with arectangular slot 20 to facilitate drilling operations. The deck is ofsufficient area to support drilling rigs, pipe racks, drawworks,engines, storage tanks, etc. The structure may be provided withsymmetrically arranged pontoons or tanks (not shown), arranged forvertical movement between guides mounted on the exterior of the shafts11. These pontoons may be of the type disclosed in US. Patent 2,528,089,issued October 31, 1950, to Siecke et al., and may include means foradjusting the position of each pontoon relative to the barge and forretaining it in its adjusted position. Also, provision may be made foradmitting and expelling water from each pontoon.

The four corner shafts 11 are each provided, as shown in FIG. 7, withrectangular spud guides which extend longitudinally through the shaftand are integral with the interior wall of the shaft. The guides passthrough the upper and lower levels of the barge, the uppermost end ofthe guide opening into the deck of the structure, the lowermost end, asshown in FIG. 3, extending through the base 17 of the barge.

Slidably disposed within each guide 21 is a spud 22 formed by a steelcasing or jacket filled with concrete, the lower end of the spud beingtapered to a point, whereby the spud is capable of piercing the soil ofthe ocean bottom. The spuds may be made up of sections, the ends of thesections being threaded to permit coupling thereof. The position of eachspud is controlled by means of tackle including a winch 23 or othersuitable means such as mechanically controlled ratchets. The Winch isoperatively coupled to the spud by means of suitable pulleys mounted ona removable frame 24 erected on the deck.

When the floating structure is in the position shown in FIG. 6, asubmergence of the structure is effected by admitting water into thebarge compartments until its free board is reduced and yet it is safelystable. The

of the structure is hung on the spuds. Additional water.

is then admitted to the barge until the buoyancy of the shafts 11 and ofthe pontoons, if such are used, becomes operative. The pontoons are thenheld at the Water level and the structure is further submerged byintroducing more water to the barge, water being added until thestructure is held up by the spuds.

The tension on the tackle holding the structure is then reduced and thestructure lowered until. the barge is resting on the bottom. Water isthen admitted into the barge and the corner shafts to a predeterminedheight such that the maximum bearing on the soil does not exceed apredetermined value. The pontoons or tanks may then i be removed or, ifdesired, may be filled with water and lowered to the top of the barge.

The structure may also be lowered by means of the spuds only, withoutusing pontoons, or by means of the pontoons only and the spuds loweredafter the barge is on the bottom. When the base of the barge is firmlyset i on the bottom, the various pieces of equipment and removablemachinery are assembled on the platform, and the structure is ready foroperation.

To refloat the structure an amount of Water is removed from the barge toreduce the pressure on the soil to zero. The suction on the bottom ofthe barge is 3 then broken by pulling up the structure by means of thetackle between the top of the structure and the top of the spuds, or bymeans of the pontoons which are raised to float with a low free boardand the water pumped out from them to increase their buoyancy and thusbreak the suction between the ground and the barge, or the suction maybe broken by any other well known manner such as air jets. The structureis then raised in the reverse manner to that set forth for lowering.

Lowering and Raising The procedure by which the barge is raised orlowered by means of the spuds will now be described in greater detail ina particular example giving spud dimensions.

The spuds are set in the barge structure before it is moved to thedrilling site, the spuds being positioned such that the pointed ends areflush with the bottom of the barge. Each spud is rigged to the top ofthe platform in a manner so that when the barge is above the desiredsite and the spuds are dropped, tension can be exerted to resist thelowering of the structure when sinking or to assist in raising thestructure when refloating.

There are four spuds, one each for each corner shaft, the length of eachspud being say approximately 125 ft. The spuds are preferably made up:in sections, as follows: One section ft. long, with its end tapered andfilled with concrete for about 30 ft.; two 20 ft. sections, and onespecial 5 ft. section with eyes firmly connected for rigging purposes.The sections are threaded with couplings for easy assembly. A specialflange 25 (FIG. 6) is provided for clamping around the spud to hold itin suspension during flotation.

When the barge is oriented in its: final location, the two 20 footsections and the 5 ft. special section is attached to the spud and thespud hung from a rigging frame, applying enough tension to the rig tohave spuds hung from the rig. The clamped flange is then loosened andthe spuds lowered until they fetch up in the ground under their ownweight. Water is: then filled in the barges gradually and the bargelowered, keeping a reasonable tension on the tackle holding the bargeson the spuds.

'[his will sink the spuds until they fetch up solidly in the ground.

When the spuds have fetched up, the barge is lowered to the bottom andall chambers filled up to their full capacity. The top foot section, ormore, of the spuds that projects above the platform is then removed, theflanges are clamped on tight at the level of the top of the platform andthe rig is then ready for operation. Some of the water may then bepumped out from the end of the barge which has the drill derrickcantilevered over it, to more nearly equalize the pressure on the bottomover the entire length.

When it becomes necessary to refloat the barge, the sections of thespuds that were previously removed are restored and the tackle replaced.The flanges are then clamped onto the spuds about one foot above theplatform. Sufficient water is then removed from the barge chambers tomake the barge slightly buoyant. Tension is then to be applied to thetackle to break the suction between the bottom of the barge and theground. The barge is then raised until it nearly touches the flanges.The flanges are then loosened and clamped a few feet higher, waterpumped out and the barge raised again. This process is repeated untilthe barge is afloat with a freeboard about two or three feet less thanthe normal freeboard of the barge.

The flanges are then clamped tight at the platform level and the bargecompletely pumped out. The buoyant force of the barge will then raisethe barge and spuds, thus breaking the skin friction on the spuds. Thespuds can then be raised with the tackle until the bottom of the spudsis flush with the bottom of the barge. The barge is then in its originaltowing position and hence can be floated to a new position.

While there has been shown what is considered to be a preferredembodiment of the invention, it will be manifest that many changes andmodifications may be made therein without departing from the essentialspirit of the invention. It is intended, therefore, to cover in theannexed claims all such changes and modifications falling within thetrue scope of the invention.

What is claimed is:

1. A submergible floating structure comprising a buoyant barge, aplurality of hollow shafts attached to said barge and extendingvertically thereabove, a working platform mounted at the upper ends ofsaid shafts, spud guides extending through said platform, said shaftsand said barge, said guides being integral with the interior wall ofsaid shafts, spuds slidable in said guides, said spuds being lowerablefor insertion into the ocean floor,

and tackle means coupled between said spuds and said platform forcontrollably guiding said structure from said spuds as the barge islowered to the ocean floor or raised therefrom.

2. A structure as set forth in claim 1 wherein said spuds areconstituted by metal casings filled with concrete and tapered at thelower end to a point to pierce the soil of the ocean floor.

3. A submergible floating structure for offshore operations comprising abuoyant barge constituted by two sep arate levels, each of which isdivided into water-tight compartments, a pump means in the centercompartment in one level to expel water from selected compartments ofsaid barge to render said barge buoyant, valve means in the centercompartment in the other level controllably to admit water in saidselected compartments, a plurality of hollow shafts attached to the topwall of said barge and extending vertically therefrom, a platformmounted at the upper end of said shaft, spud guides passing through saidshafts and through said platform and said barge, said guides each beingintegral with the interior wall of said shafts and spuds slidable insaid guides whereby said spuds may be extended therethrough for guidingsaid structure as the barge is lowered to an ocean floor or raisedtherefrom.

4. A structure as set forth in claim 3 further including tackle means tosuspend said platform fromthe upper ends of said spuds.

References Cited in the file of this patent UNITED STATES PATENTS720,997 Becker Feb. 17, 1903 720,998 Becker Feb. 17, 1903 1,908,714Schneider May 16, 1933 2,168,269 Orr et al. Aug. 1, 1939 2,237,387Crites Apr. 8, 1941 2,536,908 Chadwick Jan. 2, 1951 2,551,375 HaywardMay 1, 1951 2,579,703 Rutledge Dec. 25, 1951 2,589,146 Samuelson Mar.11, 1952 2,652,693 Goldman Sept. 22, 1953 2,675,681 Dawson Apr. 20, 19542,691,272 Townsend et a1 Oct. 12, 1954 2,699,042 Hayward Ian. 11, 1955FOREIGN PATENTS 551,449 Great Britain Feb. 23, 1943 600,129 GreatBritain Apr. 1, 1948

1. A SUBMERGIBLE FLOATING STRUCTURE COMPRISING A BUOYANT BARGE, APLURALITY OF HOLLOW SHAFTS ATTACHED TO SAID BARGE AND EXTENDINGVERTICALLY THEREABOVE, A WORKING PLATFORM MOUNTED AT THE UPPER ENDS OFSAID SHAFTS, SPUD GUIDES EXTENDING THROUGH SAID PLATFORM, SAID SHAFTSAND SAID BARGE, SAID GUIDES BEING INTEGRAL WITH THE INTERIOR WALL OFSAID SHAFTS, SPUDS SLIDABLE IN SAID GUIDES, SAID SPUDS BEING LOWERABLEFOR INSERTION INTO THE OCEAN FLOOR, AND TACKLE MEANS COUPLED BETWEENSAID SPUDS AND SAID PLATFORM FOR CONTROLLABLY GUIDING SAID STRUCTUREFROM SAID SPUDS AS THE BARGE IS LOWERED TO THE OCEAN FLOOR OR RAISEDTHEREFROM.